At my old house I didn't have these issues. I didn't check water parameters and fish were doing just fine. In the new house things changed. I've been here for over a year now and I've finally made a breakthrough. PH! I still hadn't bothered checking it, but something told me to take a sample to my local lfs. It was extremely acidic. I couldn't believe it. I have chlorinated city water and the last thing I expected was an acidic reading. I siphon gravel, clean filters etc. So, I bought a PH test kit and I had to check my own tank water and sure enough it was acidic--6.0 or less. When I checked the tap water it's well over 8! So I decided to take a small bucket of tap water which I aerated and then let stand for 48 hours testing after 24 hrs then 48. The PH is at neutral exactly. So my tap water has no buffering ability?

So, to make a long story short, over the course of 48 hours, I brought the PH up to 6.8-7.0 by adding crushed coral. I began with 3/4 of a cup for a 55 gallon, and tested after 24 hrs. Went up to 6.4. Then added another 1/2 cup to bring to current level after an additional 24 hrs. Also, and this is the most exciting change, the mopey clowns have come alive again ( I added an air stone bar too ). AND the roots of the golden pothos that I have in the tank and filter to help aid in nitrate removal have taken off!! They have noticeably grown over the last few days. I can't believe it! So is it safe to say the roots don't thrive in such an acidic atmosphere?

So, I'm thrilled with these positive changes. I'm tickled many shades of pink and I wanted to share my joy. Maybe someone who has similar struggles and issues can get something out of this. My nitrates are at about 20 after another water change but I'm hoping the plants can really do their job now. The initial nitrate test out of the tap is zero, but wonder if that reading could change if I leave the water out after 24 hrs? Something tells me that won't make a difference but going to try just the same.

Plants and fish need the minerals we usually test as GH: Calcium and Magnesium. I would also test that just to make sure this also is OK.

KH is a test for Carbonates. Beneficial microorganisms use the carbon in carbonates. When they cannot get it they do not grow much at all, and do a very poor job of turning ammonia into nitrite then nitrate.
When the KH is low the pH is often low, but is easy to change.
When the pH is low many plants and animals cannot function correctly. Plants cannot get the nutrients they need, and certain fish cannot do what they need to very well.

Adding crushed coral adds several minerals and carbonates to the water, and helps both GH and KH. In raising the KH, it also (usually) raises the pH.

Yes, Diana, I'm thrilled with the results. Today I tested GH and KH. KH must have been non existent prior to the crushed coral since it's only at approx 2.2 (40 ppm) according to API test. GH is great for the type of fish I have which is approx 3.4 (60 ppm).

Disappointly, my chronic problem, nitrate, really doesn't improve. I can't get it below 40 ppm. I'm going to try a Nitrazorb which I'm getting tonight. No, I haven't taken measures to reduce bioload. If I could find someone locally to adopt the five silver dollars, I guess that would solve the nitrate problem. I don't want to drop them off at an lfs because I'd like them to go to a proper home. They have acclimated so well, a few of them will eat from the frozen food cube I'm holding between my fingers. I know I'm to feed frozen food much more sparsely and I have.